It never ceases to amaze me that so many varieties of bread are the result of just four simple ingredients. Combine the first three, flour, water, and salt, and the result is a hard tasteless cracker, the kind sailors used to gnaw on. Once we invite yeast into the mix, however, the magic starts to happen.
Yeast is a single-celled organism in the kingdom Fungi. That means it is neither a plant, nor an animal. It can be found on grains and fruits, such as grapes, as a white dusty film. In order to survive and reproduce, yeast requires moisture, oxygen, warm temperature, and food. Yeast feeds on sugars in a process called fermentation. The chemical equation is as follows:
C6H12O6 + Yeast = 2 CO2 + 2 CH3CH2OH + 22 Kcal
dextrose + Yeast = carbon dioxide + ethyl alcohol + HEAT
Baker’s yeast, the kind you buy in the super market as “active dry yeast,” or “instant yeast,” is a specific strain that has been isolated for its ability to rapidly produce gas. Most of the bread you find in the super market is made with baker’s yeast and some glucose or high fructose corn syrup in the dough for yeast food. This results in the rapid leavening of the dough and good oven spring in the final bread. As you can see in the equation above, once the bread is out of the oven, the carbon dioxide will be released into the air, the alcohol would have evaporated in the oven, and any heat will dissipate. So the yeast has done its job raising our loaf, but the flavor is unaffected. This is great for a bakery interested in producing the most bread in the least amount of time, but nothing special for you.
Here’s where I will tell you what is so great about wild yeast.
In the wild, yeast has formed a partnership with a friendly bacteria. Now, don’t get squeamish on me, not all bacteria are bad, in fact microbiologists are just beginning to uncover the many ways microbes are beneficial to us. Lactobacilli breaks down carbohydrates into simple sugars providing food for the yeast. The by-product of this is lactic and acetic acid. This is what gives sourdough bread its signature tanginess. In fact, Lactobacilli sanfrancisensis, the dominant strain found in San Francisco sourdough, is responsible for the world famous flavor of the Bay Area’s signature bread.
The mother starter is the the ecosystem cared for by the baker to support the growth of a healthy environment of yeast and lactobacilli. The conditions of the ecosystem will determine which species move in and call it home and ultimately determine the flavor of the bread. If every region has its own unique microflauna, then sourdough bread is the most local food you can get.
If your mouth is starting to water just thinking about slicing into a Starkville Sourdough, I encourage you to sign up for our email newsletter below or “like” us on Facebook so we can keep you notified as we get ready for the opening of the 2014 Starkville Community Market.